The CanX-7 nanosatellite built by Space Flight Laboratory (SFL) at the University of Toronto Institute for Aerospace Studies (UTIAS) has validated real-time detection and tracking of aircraft by satellite in low-Earth orbit. The next mission phase will begin in early May with deployment of drag sails developed by SFL to accelerate the deorbiting of small satellites as a practical solution to the space debris problem.

SFL, a provider of complete microspace missions, developed CanX-7 on its space-proven nanosatellite bus carrying two payloads: the Automatic Dependent Surveillance – Broadcast (ADS-B) aircraft tracking receiver manufactured by the Royal Military College of Canada (RMC) with support from SFL, and the modular drag sail system. Measuring 10x10x34cm, the 3.5-kilogram nanosat was launched on Sept. 26, 2016, from India.

“The ADS-B instrument on CanX-7 has received and decoded 3.6 million signals from aircraft in less than six months,” said Dr. Robert E. Zee, SFL Director. “This mission proves that global real-time aircraft tracking can be achieved with a low-cost, responsive constellation of small satellites.”

Having launched several small satellites for marine vessel tracking, SFL teamed with RMC and COM DEV Ltd. (now Honeywell) to address the challenges of monitoring aircraft over the ocean and other remote areas. Every second, aircraft broadcast ADS-B signals with position, velocity and status data, but receivers are traditionally located only at ground stations or in other aircraft with limited reception. CanX-7 was the first Canadian nanosatellite to receive and decode ADS-B signals in real time from space, confirming that global aircraft tracking is possible and practical.

“CanX-7 is providing valuable information on received signal levels and aircraft antenna radiation patterns, which will allow us to verify and refine our signal propagation model,” said Dr. Ron Vincent, Director of the RMC Centre for Space Research.

Once the ADS-B validation is completed in late April or early May, the deorbit demonstration will be initiated, contributing to Canada’s cooperation with the Inter-Agency Debris Coordination Committee (IADC). This committee has released guidelines on satellite deorbit measures that are required to mitigate orbital debris problems. With funding from Defence R&D Canada, NSERC, and COM DEV, SFL designed and built the modular drag sail system on CanX-7.

“This is the first drag sail deorbit technology developed and launched by Canada,” said Zee. “The modular design will enable this system to deorbit almost any small satellite up to 100 kilograms in mass.”

The four one-squared-meter sails will be deployed sequentially with commands from the SFL ground station in Toronto. Onboard sensors will monitor their deployment. The sails will increase drag on the satellite and accelerate orbital decay over a few years to the point where it will burn up in the atmosphere. Without the potential use of sail technology demonstrated by CanX-7, some small satellites could potentially stay in low Earth orbit for more than 25 years, posing collision risks to other low-Earth satellites and the International Space Station.